We got a major event coming up and specially now the event manager stops working for most users.

Most users use normal browsers to subscribe, and they were all complaining about the event tregistration wich not working.
They told me after submitting, the loading circle keeps going on and nothing happens.

First i couldn't reproduce the error, but after trying on my iphone and ipad i get the same error.

Guys, you update to the latest versions to fast. this is a general issue for all plugins. Wait or at least test all functionality on a test system before rolling out the latest releases on PROD.
I suggest, for the time being to revert to the last known good and working version of EM and wait on a parallel system for an update that resolves the issue.
As it can easily be also an issue introduced by other plugins than EM, you should also list here the other plugins you used or that have been updated recently. They could also make other plugins, like EM, stop working.

You particular case sounds like a Javascrpt library issue.
- I assume it was working before with Mobiles ?
- What theme do you use ?
- What other plugins
- What where the recent changes on your system since the last working booking ?
- Is the system working again when you go a previous version of EM ? (what was the last EM version that worked ?)
- ...
This makes it easier for Marcus to analyse the source of the issue and whetehr it is actually EM.